Facebook for iPhone and Facebook for Android were both updated this week. You can grab Facebook for iPhone 3.4.1 from the Apple App store on iTunes while Facebook for Android 1.5.3 is available from Google's Android Market.

Here is the official changelog for Facebook for iPhone 3.4.1:

Find your Friends on Facebook using your phone

Add your phone to your profile

Bug fixes

Here is the official changelog for Facebook for Android 1.5.3:

Added the ability to tag friends in status updates

Added Find Friends feature

Added the ability to add your phone number to your profile

The most important part is that Facebook has added the Find Friends feature to both apps, allowing users to search through their device's contacts and send them friend requests on, or invites to, the social network. The updated apps also prompt users to add their phone number to their profile if they haven't already.

Facebook's Find Friends feature has always been about increasing the number of connections on the social network, gaining more users in total, and (thus) generating more traffic for the site. Porting the feature to the mobile apps is just natural progression and makes sure that the social network continues to grow.

By encouraging users to add their phone numbers, however, Facebook is looking to the future of computing, which is of course largely mobile. We already know the company is very interested in mobile messaging and it wants as many of its users as possible to be comfortable with including their phone number on the site. That way, when Facebook begins offering services that require a mobile number, most users won't have to debate whether to give it to Facebook.

For those interested, AppData tracks app usage on Facebook. Facebook for iPhone has 39.8 million daily active users and 72.0 million monthly active users. Facebook for Android has 23.71 million daily active users and 35.98 million monthly active users.